package com.chinathinks.core.net.ftp;

import java.text.DateFormatSymbols;
import java.util.Collection;
import java.util.Locale;
import java.util.Map;
import java.util.StringTokenizer;
import java.util.TreeMap;

/**
 * <p>
 * This class implements an alternate means of configuring the
 * {@link org.apache.commons.net.ftp.FTPClient FTPClient} object and also
 * subordinate objects which it uses. Any class implementing the
 * {@link org.apache.commons.net.ftp.Configurable Configurable } interface can
 * be configured by this object.
 * </p>
 * <p>
 * In particular this class was designed primarily to support configuration of
 * FTP servers which express file timestamps in formats and languages other than
 * those for the US locale, which although it is the most common is not
 * universal. Unfortunately, nothing in the FTP spec allows this to be
 * determined in an automated way, so manual configuration such as this is
 * necessary.
 * </p>
 * <p>
 * This functionality was designed to allow existing clients to work exactly as
 * before without requiring use of this component. This component should only
 * need to be explicitly invoked by the user of this package for problem cases
 * that previous implementations could not solve.
 * </p>
 * <h3>Examples of use of FTPClientConfig</h3> Use cases: You are trying to
 * access a server that
 * <ul>
 * <li>lists files with timestamps that use month names in languages other than
 * English</li>
 * <li>lists files with timestamps that use date formats other than the American
 * English "standard" <code>MM dd yyyy</code></li>
 * <li>is in different timezone and you need accurate timestamps for dependency
 * checking as in Ant</li>
 * </ul>
 * <p>
 * Unpaged (whole list) access on a UNIX server that uses French month names but
 * uses the "standard" <code>MMM d yyyy</code> date formatting
 * 
 * <pre>
 * FTPClient f = FTPClient();
 * FTPClientConfig conf = new FTPClientConfig(FTPClientConfig.SYST_UNIX);
 * conf.setServerLanguageCode(&quot;fr&quot;);
 * f.configure(conf);
 * f.connect(server);
 * f.login(username, password);
 * FTPFile[] files = listFiles(directory);
 * </pre>
 * 
 * </p>
 * <p>
 * Paged access on a UNIX server that uses Danish month names and "European"
 * date formatting in Denmark's time zone, when you are in some other time zone.
 * 
 * <pre>
 * FTPClient f = FTPClient();
 * FTPClientConfig conf = new FTPClientConfig(FTPClientConfig.SYST_UNIX);
 * conf.setServerLanguageCode(&quot;da&quot;);
 * conf.setDefaultDateFormat(&quot;d MMM yyyy&quot;);
 * conf.setRecentDateFormat(&quot;d MMM HH:mm&quot;);
 * conf.setTimeZoneId(&quot;Europe/Copenhagen&quot;);
 * f.configure(conf);
 * f.connect(server);
 * f.login(username, password);
 * FTPListParseEngine engine = f.initiateListParsing(&quot;com.whatever.YourOwnParser&quot;, directory);
 * 
 * while (engine.hasNext()) {
 * 	FTPFile[] files = engine.getNext(25); // &quot;page size&quot; you want
 * 	// do whatever you want with these files, display them, etc.
 * 	// expensive FTPFile objects not created until needed.
 * }
 * </pre>
 * 
 * </p>
 * <p>
 * Unpaged (whole list) access on a VMS server that uses month names in a
 * language not {@link #getSupportedLanguageCodes() supported} by the system.
 * but uses the "standard" <code>MMM d yyyy</code> date formatting
 * 
 * <pre>
 * FTPClient f = FTPClient();
 * FTPClientConfig conf = new FTPClientConfig(FTPClientConfig.SYST_VMS);
 * conf.setShortMonthNames(&quot;jan|feb|mar|apr|ma\u00ED|j\u00FAn|j\u00FAl|\u00e1g\u00FA|sep|okt|n\u00F3v|des&quot;);
 * f.configure(conf);
 * f.connect(server);
 * f.login(username, password);
 * FTPFile[] files = listFiles(directory);
 * </pre>
 * 
 * </p>
 * <p>
 * Unpaged (whole list) access on a Windows-NT server in a different time zone.
 * (Note, since the NT Format uses numeric date formatting, language issues are
 * irrelevant here).
 * 
 * <pre>
 * FTPClient f = FTPClient();
 * FTPClientConfig conf = new FTPClientConfig(FTPClientConfig.SYST_NT);
 * conf.setTimeZoneId(&quot;America/Denver&quot;);
 * f.configure(conf);
 * f.connect(server);
 * f.login(username, password);
 * FTPFile[] files = listFiles(directory);
 * </pre>
 * 
 * </p>
 * Unpaged (whole list) access on a Windows-NT server in a different time zone
 * but which has been configured to use a unix-style listing format.
 * 
 * <pre>
 * FTPClient f = FTPClient();
 * FTPClientConfig conf = new FTPClientConfig(FTPClientConfig.SYST_UNIX);
 * conf.setTimeZoneId(&quot;America/Denver&quot;);
 * f.configure(conf);
 * f.connect(server);
 * f.login(username, password);
 * FTPFile[] files = listFiles(directory);
 * </pre>
 * 
 * </p>
 * 
 * @since 1.4
 * @see org.apache.commons.net.ftp.Configurable
 * @see org.apache.commons.net.ftp.FTPClient
 * @see org.apache.commons.net.ftp.parser.FTPTimestampParserImpl#configure(FTPClientConfig)
 * @see org.apache.commons.net.ftp.parser.ConfigurableFTPFileEntryParserImpl
 */
public class FTPClientConfig {

	/**
	 * Identifier by which a unix-based ftp server is known throughout the
	 * commons-net ftp system.
	 */
	public static final String SYST_UNIX = "UNIX";

	/**
	 * Identifier by which a vms-based ftp server is known throughout the
	 * commons-net ftp system.
	 */
	public static final String SYST_VMS = "VMS";

	/**
	 * Identifier by which a WindowsNT-based ftp server is known throughout the
	 * commons-net ftp system.
	 */
	public static final String SYST_NT = "WINDOWS";

	/**
	 * Identifier by which an OS/2-based ftp server is known throughout the
	 * commons-net ftp system.
	 */
	public static final String SYST_OS2 = "OS/2";

	/**
	 * Identifier by which an OS/400-based ftp server is known throughout the
	 * commons-net ftp system.
	 */
	public static final String SYST_OS400 = "OS/400";

	/**
	 * Identifier by which an MVS-based ftp server is known throughout the
	 * commons-net ftp system.
	 */
	public static final String SYST_MVS = "MVS";

	private final String serverSystemKey;
	private String defaultDateFormatStr = null;
	private String recentDateFormatStr = null;
	private String serverLanguageCode = null;
	private String shortMonthNames = null;
	private String serverTimeZoneId = null;

	/**
	 * The main constructor for an FTPClientConfig object
	 * 
	 * @param systemKey
	 *            key representing system type of the server being connected to.
	 *            See {@link #getServerSystemKey() serverSystemKey}
	 */
	public FTPClientConfig(String systemKey) {
		this.serverSystemKey = systemKey;
	}

	/**
	 * Convenience constructor mainly for use in testing. Constructs a UNIX
	 * configuration.
	 */
	public FTPClientConfig() {
		this(SYST_UNIX);
	}

	/**
	 * Constructor which allows setting of all member fields
	 * 
	 * @param systemKey
	 *            key representing system type of the server being connected to.
	 *            See {@link #getServerSystemKey() serverSystemKey}
	 * @param defaultDateFormatStr
	 *            See {@link #setDefaultDateFormatStr(String)
	 *            defaultDateFormatStr}
	 * @param recentDateFormatStr
	 *            See {@link #setRecentDateFormatStr(String)
	 *            recentDateFormatStr}
	 * @param serverLanguageCode
	 *            See {@link #setServerLanguageCode(String) serverLanguageCode}
	 * @param shortMonthNames
	 *            See {@link #setShortMonthNames(String) shortMonthNames}
	 * @param serverTimeZoneId
	 *            See {@link #setServerTimeZoneId(String) serverTimeZoneId}
	 */
	public FTPClientConfig(String systemKey, String defaultDateFormatStr, String recentDateFormatStr,
			String serverLanguageCode, String shortMonthNames, String serverTimeZoneId) {
		this(systemKey);
		this.defaultDateFormatStr = defaultDateFormatStr;
		this.recentDateFormatStr = recentDateFormatStr;
		this.serverLanguageCode = serverLanguageCode;
		this.shortMonthNames = shortMonthNames;
		this.serverTimeZoneId = serverTimeZoneId;
	}

	private static Map LANGUAGE_CODE_MAP = new TreeMap();
	static {

		// if there are other commonly used month name encodings which
		// correspond to particular locales, please add them here.

		// many locales code short names for months as all three letters
		// these we handle simply.
		LANGUAGE_CODE_MAP.put("en", Locale.ENGLISH);
		LANGUAGE_CODE_MAP.put("de", Locale.GERMAN);
		LANGUAGE_CODE_MAP.put("it", Locale.ITALIAN);
		LANGUAGE_CODE_MAP.put("es", new Locale("es", "", "")); // spanish
		LANGUAGE_CODE_MAP.put("pt", new Locale("pt", "", "")); // portuguese
		LANGUAGE_CODE_MAP.put("da", new Locale("da", "", "")); // danish
		LANGUAGE_CODE_MAP.put("sv", new Locale("sv", "", "")); // swedish
		LANGUAGE_CODE_MAP.put("no", new Locale("no", "", "")); // norwegian
		LANGUAGE_CODE_MAP.put("nl", new Locale("nl", "", "")); // dutch
		LANGUAGE_CODE_MAP.put("ro", new Locale("ro", "", "")); // romanian
		LANGUAGE_CODE_MAP.put("sq", new Locale("sq", "", "")); // albanian
		LANGUAGE_CODE_MAP.put("sh", new Locale("sh", "", "")); // serbo-croatian
		LANGUAGE_CODE_MAP.put("sk", new Locale("sk", "", "")); // slovak
		LANGUAGE_CODE_MAP.put("sl", new Locale("sl", "", "")); // slovenian

		// some don't
		LANGUAGE_CODE_MAP.put("fr", "jan|f\u00e9v|mar|avr|mai|jun|jui|ao\u00fb|sep|oct|nov|d\u00e9c"); // french

	}

	/**
	 * Getter for the serverSystemKey property. This property specifies the
	 * general type of server to which the client connects. Should be either one
	 * of the <code>FTPClientConfig.SYST_*</code> codes or else the fully
	 * qualified class name of a parser implementing both the
	 * <code>FTPFileEntryParser</code> and <code>Configurable</code> interfaces.
	 * 
	 * @return Returns the serverSystemKey property.
	 */
	public String getServerSystemKey() {
		return serverSystemKey;
	}

	/**
	 * getter for the {@link #setDefaultDateFormatStr(String)
	 * defaultDateFormatStr} property.
	 * 
	 * @return Returns the defaultDateFormatStr property.
	 */
	public String getDefaultDateFormatStr() {
		return defaultDateFormatStr;
	}

	/**
	 * getter for the {@link #setRecentDateFormatStr(String)
	 * recentDateFormatStr} property.
	 * 
	 * @return Returns the recentDateFormatStr property.
	 */

	public String getRecentDateFormatStr() {
		return recentDateFormatStr;
	}

	/**
	 * getter for the {@link #setServerTimeZoneId(String) serverTimeZoneId}
	 * property.
	 * 
	 * @return Returns the serverTimeZoneId property.
	 */
	public String getServerTimeZoneId() {
		return serverTimeZoneId;
	}

	/**
	 * <p>
	 * getter for the {@link #setShortMonthNames(String) shortMonthNames}
	 * property.
	 * </p>
	 * 
	 * @return Returns the shortMonthNames.
	 */
	public String getShortMonthNames() {
		return shortMonthNames;
	}

	/**
	 * <p>
	 * getter for the {@link #setServerLanguageCode(String) serverLanguageCode}
	 * property.
	 * </p>
	 * * @return Returns the serverLanguageCode property.
	 */
	public String getServerLanguageCode() {
		return serverLanguageCode;
	}

	/**
	 * <p>
	 * setter for the defaultDateFormatStr property. This property specifies the
	 * main date format that will be used by a parser configured by this
	 * configuration to parse file timestamps. If this is not specified, such a
	 * parser will use as a default value, the most commonly used format which
	 * will be in as used in <code>en_US</code> locales.
	 * </p>
	 * <p>
	 * This should be in the format described for
	 * <code>java.text.SimpleDateFormat</code>. property.
	 * </p>
	 * 
	 * @param defaultDateFormatStr
	 *            The defaultDateFormatStr to set.
	 */
	public void setDefaultDateFormatStr(String defaultDateFormatStr) {
		this.defaultDateFormatStr = defaultDateFormatStr;
	}

	/**
	 * <p>
	 * setter for the recentDateFormatStr property. This property specifies a
	 * secondary date format that will be used by a parser configured by this
	 * configuration to parse file timestamps, typically those less than a year
	 * old. If this is not specified, such a parser will not attempt to parse
	 * using an alternate format.
	 * </p>
	 * This is used primarily in unix-based systems. </p> This should be in the
	 * format described for <code>java.text.SimpleDateFormat</code>. </p>
	 * 
	 * @param recentDateFormatStr
	 *            The recentDateFormatStr to set.
	 */
	public void setRecentDateFormatStr(String recentDateFormatStr) {
		this.recentDateFormatStr = recentDateFormatStr;
	}

	/**
	 * <p>
	 * setter for the serverTimeZoneId property. This property allows a time
	 * zone to be specified corresponding to that known to be used by an FTP
	 * server in file listings. This might be particularly useful to clients
	 * such as Ant that try to use these timestamps for dependency checking.
	 * </p>
	 * <p>
	 * This should be one of the identifiers used by
	 * <code>java.util.TimeZone</code> to refer to time zones, for example,
	 * <code>America/Chicago</code> or <code>Asia/Rangoon</code>.
	 * </p>
	 * 
	 * @param serverTimeZoneId
	 *            The serverTimeZoneId to set.
	 */
	public void setServerTimeZoneId(String serverTimeZoneId) {
		this.serverTimeZoneId = serverTimeZoneId;
	}

	/**
	 * <p>
	 * setter for the shortMonthNames property. This property allows the user to
	 * specify a set of month names used by the server that is different from
	 * those that may be specified using the
	 * {@link #setServerLanguageCode(String) serverLanguageCode} property.
	 * </p>
	 * <p>
	 * This should be a string containing twelve strings each composed of three
	 * characters, delimited by pipe (|) characters. Currently, only 8-bit ASCII
	 * characters are known to be supported. For example, a set of month names
	 * used by a hypothetical Icelandic FTP server might conceivably be
	 * specified as
	 * <code>"jan|feb|mar|apr|ma&#xED;|j&#xFA;n|j&#xFA;l|&#xE1;g&#xFA;|sep|okt|n&#xF3;v|des"</code>
	 * .
	 * </p>
	 * 
	 * @param shortMonthNames
	 *            The value to set to the shortMonthNames property.
	 */
	public void setShortMonthNames(String shortMonthNames) {
		this.shortMonthNames = shortMonthNames;
	}

	/**
	 * <p>
	 * setter for the serverLanguageCode property. This property allows user to
	 * specify a <a
	 * href="http://www.ics.uci.edu/pub/ietf/http/related/iso639.txt">
	 * two-letter ISO-639 language code</a> that will be used to configure the
	 * set of month names used by the file timestamp parser. If neither this nor
	 * the {@link #setShortMonthNames(String) shortMonthNames} is specified,
	 * parsing will assume English month names, which may or may not be
	 * significant, depending on whether the date format(s) specified via
	 * {@link #setDefaultDateFormatStr(String) defaultDateFormatStr} and/or
	 * {@link #setRecentDateFormatStr(String) recentDateFormatStr} are using
	 * numeric or alphabetic month names.
	 * </p>
	 * <p>
	 * If the code supplied is not supported here, <code>en_US</code> month
	 * names will be used. We are supporting here those language codes which,
	 * when a <code> java.util.Locale</code> is constucted using it, and a
	 * <code>java.text.SimpleDateFormat</code> is constructed using that Locale,
	 * the array returned by the SimpleDateFormat's
	 * <code>getShortMonths()</code> method consists solely of three 8-bit ASCII
	 * character strings. Additionally, languages which do not meet this
	 * requirement are included if a common alternative set of short month names
	 * is known to be used. This means that users who can tell us of additional
	 * such encodings may get them added to the list of supported languages by
	 * contacting the jakarta-commons-net team.
	 * </p>
	 * <p>
	 * <strong> Please note that this attribute will NOT be used to determine a
	 * locale-based date format for the language. </strong> Experience has shown
	 * that many if not most FTP servers outside the United States employ the
	 * standard <code>en_US</code> date format orderings of
	 * <code>MMM d yyyy</code> and <code>MMM d HH:mm</code> and attempting to
	 * deduce this automatically here would cause more problems than it would
	 * solve. The date format must be changed via the
	 * {@link #setDefaultDateFormatStr(String) defaultDateFormatStr} and/or
	 * {@link #setRecentDateFormatStr(String) recentDateFormatStr} parameters.
	 * </p>
	 * 
	 * @param serverLanguageCode
	 *            The value to set to the serverLanguageCode property.
	 */
	public void setServerLanguageCode(String serverLanguageCode) {
		this.serverLanguageCode = serverLanguageCode;
	}

	/**
	 * Looks up the supplied language code in the internally maintained table of
	 * language codes. Returns a DateFormatSymbols object configured with short
	 * month names corresponding to the code. If there is no corresponding entry
	 * in the table, the object returned will be that for <code>Locale.US</code>
	 * 
	 * @param languageCode
	 *            See {@link #setServerLanguageCode(String) serverLanguageCode}
	 * @return a DateFormatSymbols object configured with short month names
	 *         corresponding to the supplied code, or with month names for
	 *         <code>Locale.US</code> if there is no corresponding entry in the
	 *         internal table.
	 */
	public static DateFormatSymbols lookupDateFormatSymbols(String languageCode) {
		Object lang = LANGUAGE_CODE_MAP.get(languageCode);
		if (lang != null) {
			if (lang instanceof Locale) {
				return new DateFormatSymbols((Locale) lang);
			} else if (lang instanceof String) {
				return getDateFormatSymbols((String) lang);
			}
		}
		return new DateFormatSymbols(Locale.US);
	}

	/**
	 * Returns a DateFormatSymbols object configured with short month names as
	 * in the supplied string
	 * 
	 * @param shortmonths
	 *            This should be as described in
	 *            {@link #setShortMonthNames(String) shortMonthNames}
	 * @return a DateFormatSymbols object configured with short month names as
	 *         in the supplied string
	 */
	public static DateFormatSymbols getDateFormatSymbols(String shortmonths) {
		String[] months = splitShortMonthString(shortmonths);
		DateFormatSymbols dfs = new DateFormatSymbols(Locale.US);
		dfs.setShortMonths(months);
		return dfs;
	}

	private static String[] splitShortMonthString(String shortmonths) {
		StringTokenizer st = new StringTokenizer(shortmonths, "|");
		int monthcnt = st.countTokens();
		if (12 != monthcnt) {
			throw new IllegalArgumentException("expecting a pipe-delimited string containing 12 tokens");
		}
		String[] months = new String[13];
		int pos = 0;
		while (st.hasMoreTokens()) {
			months[pos++] = st.nextToken();
		}
		months[pos] = "";
		return months;
	}

	/**
	 * Returns a Collection of all the language codes currently supported by
	 * this class. See {@link #setServerLanguageCode(String) serverLanguageCode}
	 * for a functional descrption of language codes within this system.
	 * 
	 * @return a Collection of all the language codes currently supported by
	 *         this class
	 */
	public static Collection getSupportedLanguageCodes() {
		return LANGUAGE_CODE_MAP.keySet();
	}

}
